The present invention relates to a game machine using self-propelled members, and more particularly, to a racing game machine which facilitates travel control of the self-propelled members, significantly simplifies a mechanical structure and control system of the game machine, and significantly curtails manufacturing costs.
A travel driving mechanism of a self-propelled member used in a racing game machine basically drives wheels by a rotary drive motor and effects turning action by controlling a rotational speed differential between the left driving wheel and the right driving wheel. Japanese Patent No. 2650643 discloses an example of such a racing game machine. In the racing game machine, a racing track is formed into a two-story structure in which self-propelled members are caused to travel on a traveling field to attractively guide miniatures which are incapable of self-propelling are caused to race with each other on a racing track by way of magnetic force originating from magnets.
Electrical wires are arranged in the X and Y directions densely on a plane on which the self-propelled members travel (hereinafter called as traveling field). The electrical wires serve as position detecting wires to detect traveling positions of the self-propelled members. On the basis of detected position information, the self-propelled members are subjected to feedback control, thereby implementing trackless travel. A known position detecting method includes the steps of: capturing a self-propelled member by a CCD camera, subjecting the thus-captured image to image processing, and detecting a traveling position of the self-propelled member on a virtual traveling field through computation.
Nowadays, the information processing speed of a microcomputer and the information storage capacity of memory have been remarkably improved. Against this backdrop, feedback control of travel of a self-propelled member on the position detecting information is comparatively easy in terms of technique.
However, in an actual racing game machine, a self-propelled member travels through use of driving wheels. As a result of slippage, the member may be thrown into a skid and deviate from a racing track, become greatly deviated from a desired direction, or overturn. Thus, feedback control poses a problem in the accuracy of control of a traveling route, in the response of correction of a traveling direction of a self-propelled member, and in the response of correction of a track of the self-propelled member. In reality, unexpected racing is effected often. Thus, difficulty is encountered in causing self-propelled members to race with each other as planned.
On the premise that self-propelled members would cause slippage and deviate from tracks, a plurality of self-propelled members are simultaneously controlled so as to travel by effecting feedback control on the basis of position detecting information while correction is made to movement of the self-propelled members. In this case, a control system and a control program become complicated.
Even in the case of a member which travels, drives, and turns by frictional force developing between wheels and a travel face, it is theoretically conceivable that the member effects feedforward control instead of feedback control on the basis of position detecting information. It is readily predicted that a travel control program for the member and design thereof would be simple. Considerable difficulty is encountered in causing a plurality of self-propelled members in a game machine to accurately travel along predetermined traveling paths through feedforward control. Causing self-propelled members to race with each other in a racing game machine through such feedforward control as planned is almost impossible.
In relation to travel control operation based on feedback control as described the above, the traveling position of a self-propelled member is detected successively, and arithmetic operation is performed on the basis of the thus-detected position so that the traveling is controlled in accordance with a predetermined program. However, in such a configuration, a position sensor, an information processing system, and a travel control system are complicated and involve considerably high manufacturing costs.